ROVER 3500 POOR HOT STARTING
Q
I have a 1969 Rover P5 3500 Coupé which starts easily from cold and runs well, but if I stop for a short time and then attempt to restart, the engine will just spin over without starting. I need to let the engine cool right down before it will then restart without problems. When this occurred recently, my friend removed the spark plugs to find that they were wet, and after drying them off I was able to start the engine easily again. Why does this only occur when the engine is hot? Ben Foute
AI would suspect that the problem is with the float level in the carburettors. Slight wear on the needle valve allows the fuel level to rise above the optimum level slightly. This will give few problems to the running engine, but when stopped, the higher float chamber level will allow a small amount of fuel to run into the inlet manifold. When attempting to restart after only a short time, this will give too rich a mixture, and as you have discovered can flood the engine. Once the engine has been left a while and cooled down, the fuel deposited into the manifold will partially evaporate, but any left will simply give the richer mixture that the engine would naturally need to start from cold. Adjusting the float levels should remedy the situation, and you may also find that you can improve your mpg figures slightly. When doing this, I would also check the float to ensure that a small amount of fuel has not crept inside – a quick shake will normally reveal any such problems.